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Iboost power question
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NoobSolar
Posts: 117 Forumite

My iboost setup is new. I love it, obviously. But can anyone tell me how much energy in KWH (in their experience) it takes for an iboost to heat a large tank (250l) from cold? Mine put over 13 kwh into it one day and the water was lovely and warm, but I still don't know how much energy it would take two 3000W immersions to heat a tank of water.
London. 6.4kwh system, South facing. 16 Hyundai 400kw all black panels w/ optimisers, 6kw Solaredge HD Wave inverter, Solar Iboost with two immersion heaters on one 240l hw tank. Octopus Flux. Ivar 5 Wood Burning Stove. Leaf 62kwh plus Zappi. Two chickens: 1 Light Sussex, 1 Speckled Rock. Omlet walk-in run. Approx 1.5 eggs per day egg generation rate using Marriage's organic layers pellets.
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28.6 kWh is needed to heat 250litres of water from 10c to 60c so it would take around 9.5 hours. (The iBoost will only send power to one heater at once.)Northern Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, Solar IBoost water heater, Mitsubishi SRK35ZS-S and SRK20ZS-S Wall Mounted Inverter Heat Pumps, ex Nissan Leaf owner)0
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IF you have a blending valve on your hot water outlet (or on every hot tap) then it make sense to heat the tank as hot as you can without triggering the safety cut-out. To about 75 C, perhaps?Reed0
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I have a 140 litre tank and a 28 inch top mounted immersion and it takes 4 to 5 kwh a day to get to 70 degrees,1
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JKenH said:28.6 kWh is needed to heat 250litres of water from 10c to 60c so it would take around 9.5 hours. (The iBoost will only send power to one heater at once.)
I've been looking into tanks a bit lately so this post caught my eye
West central Scotland
4kw sse since 2014 and 6.6kw wsw / ene split since 2019
24kwh leaf, 75Kwh Tesla and Lux 3600 with 60Kwh storage0 -
It takes 0.6 kWh to heat 10 litres of water by 50C.Multiply that to suit the size of your tank.N. Hampshire, he/him. Octopus Intelligent Go elec & Tracker gas / Vodafone BB / iD mobile. Ripple Kirk Hill member.
2.72kWp PV facing SSW installed Jan 2012. 11 x 247w panels, 3.6kw inverter. 34 MWh generated, long-term average 2.6 Os.Not exactly back from my break, but dipping in and out of the forum.Ofgem cap table, Ofgem cap explainer. Economy 7 cap explainer. Gas vs E7 vs peak elec heating costs, Best kettle!0 -
Solarchaser said:JKenH said:28.6 kWh is needed to heat 250litres of water from 10c to 60c so it would take around 9.5 hours. (The iBoost will only send power to one heater at once.)
I've been looking into tanks a bit lately so this post caught my eyeNorthern Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, Solar IBoost water heater, Mitsubishi SRK35ZS-S and SRK20ZS-S Wall Mounted Inverter Heat Pumps, ex Nissan Leaf owner)0 -
Thanks for so many useful comments. I am finding similar things : my iboost is putting through between 7 and 9 kwh typically, on days where we don't quite run out of hot water, in a 240 litre tank. It did 13kwh once on a cold tank also used for a midday bath.
London. 6.4kwh system, South facing. 16 Hyundai 400kw all black panels w/ optimisers, 6kw Solaredge HD Wave inverter, Solar Iboost with two immersion heaters on one 240l hw tank. Octopus Flux. Ivar 5 Wood Burning Stove. Leaf 62kwh plus Zappi. Two chickens: 1 Light Sussex, 1 Speckled Rock. Omlet walk-in run. Approx 1.5 eggs per day egg generation rate using Marriage's organic layers pellets.1 -
If nothing else, this thread is a timely reminder of how much energy water-heating gobbles up.
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Yes Indeed.
Got an email from octopus to say gas will go over 7p in a couple of weeks time.
With gas 75% efficient and electric at 99% for heating, I think it's definitely time to switch to electric water heating... and maybe electric house heatingWest central Scotland
4kw sse since 2014 and 6.6kw wsw / ene split since 2019
24kwh leaf, 75Kwh Tesla and Lux 3600 with 60Kwh storage0
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